From Bringewald, U.S. Pat. No. 3,847,004, there is known an apparatus for applying pressure, which includes a pressure base, pressure means vertically spaced above the pressure base to define a pressure zone, means for conveying work between the pressure base and the pressure means, and wherein one of the pressure base and the pressure means is inclined in the direction the work is conveyed. Rollers convert sliding friction into rolling friction as the work passes through the pressure zone, and means are provided for guiding the rollers as they pass under the pressure zone. An auxiliary pressure unit is adjustably mounted on the pressure means; additionally guide means are provided for the rollers as they pass under the pressure means, as well as adjusting means for adjusting the guide means to compensate for movement between the pressure means and the auxiliary pressure unit.
From Bringewald, U.S. Pat. No. 3,521,472, there has become known a process and an apparatus for the production of parts from ductile materials with integral stiffeners on one or both sides, and from Bringewald, U.S. Pat. No. 3,425,095 there has become known a process and an apparatus for producing metal plates with integral stiffeners.
The Bringewald U.S. Pat. No. 3,847,004, which postdates the Bringewald U.S. Pat. Nos. 3,521,472 and 3,425,098 references by approximately 4 and 6 years, respectively, is believed to be the closest reference to the present invention.
The Bringewald U.S. Pat. No. 3,847,004 patent has, however, several disadvantages. A principal disadvantage is the fact the rollers are linked together by the links, so as to form a chain, which in turn, has peaks and valleys on an outer surface thereof. As the work support is transported only by being disposed on a lower chain, slippage occurs between the work support and the lower chain, if the upper front edge of the frontmost force-translating element happens to lodge in one of the valleys, thus restraining any forward movement of the force-translating elements. This slippage cannot be eliminated if the work support is transported forwardly at a greater pull, or force. Furthermore, as pressure is initially exerted on the frontmost force-translating element downwardly, it will move downwardly, leaving a step between it and the next force-translating element. The resulting step can give rise to slippage again in a manner analogous to that caused by the front edge of the frontmost force-translating element. Such a slippage, in turn, causes firstly a non-uniform pressure being exerted on the work, and secondly a slow-down in the operation of the part-forming apparatus. Such a non-uniform pressure, in turn, causes the part to be formed with some deformities, at best resulting in non-uniform parts shaped by the apparatus according to Bringewald; thus a part made during one run does not necessarily resemble a part made during another run of the Bringewald apparatus.